I see your willing to make a first person game, and i’ll try to help you some with that.
If you have your gun placed where your spawning point shall be in the game,
select your camera and grab it to the left of your gun/weapon where u want it (Press 0 on your numpad to have a better view for it and when starting your game) then select your gun/weapon with rightclick & then hold shift & rightclick on your camera and press ctrl+P
this will parent the gun and the camera. Or you can do it otherwise by selecting the camera first then your weapon. You have to choose which object your going to give the logic bricks. For further info i would suggest you to check out the full firstperson view with mouselook tutorial, it’s explained really clearly: